Title: Supernova-induced binary-interaction-powered supernovae: a model for SN2022jli
Authors: Ryosuke Hirai (平井遼介), Philipp Podsiadlowski, Peter Hoeflich, Maxim V. Barkov, Conrad Chan, David Liptai, and Shigehiro Nagataki (長瀧重博)
First Author’s Institution: Astrophysical Big Bang Laboratory, RIKEN Pioneering Research Institute, Japan; School of Physics and Astronomy, Monash University, Victoria, Australia; OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery, Australia
Status: Submitted to AAS Journals [preprint open access on arXiv]
There are thousands of dying stars that go bang in the night. These explosions are known as supernovae (SNe), and they are classified primarily on what spectral lines they show in the days and weeks following their initial explosion. Most broadly, they are separated into type I (spectra that show little or no evidence of hydrogen) and type II (spectra that show hydrogen). The physics leading to each type of supernova (SN) is different, and astronomers use all of the information at their disposal to learn about these cosmic fireworks.
One of the most useful tools in monitoring and learning about supernovae is their light curve – the plot of the explosion’s brightness over time. This light curve usually appears as a steep incline up to a peak in brightness several days after the initial detonation, and then a shallow decline in brightness over the proceeding several weeks. There are, however, a few examples of supernovae which break this mould.
Today’s paper seeks to understand the curious case of supernova SN2022jli. Unlike the typical gradual fade in brightness, the light curve of this supernova shows a periodic bump of brightness every 12.5 days (see Figure 1). The proposed mechanisms to explain this include the blown-apart supernova material interacting with concentric and regularly spaced shells of circumstellar matter, or a binary companion that interacts with the supernova remnant each orbital period. The authors of today’s paper investigate the latter scenario by running 3D hydrodynamical simulations of an interacting, post-SN binary to try to recover SN2022jli’s periodic light curve and constrain the orbital characteristics of the system.
The authors only have the supernova’s light curve to go off of, so they explore a range of orbital scenarios to explain SN2022jli. They run a series of models evolving a neutron star (NS) – the degenerate core left over after a low-mass SN – together with a main-sequence stellar companion, varying the orbital eccentricity and companion mass, while fixing the orbital period (at the observed 12.5 day oscillatory period) and NS mass to 1.4 solar masses – a typical mass for a newborn NS.
Why a neutron star? SN2022jli is a sub-class of Type I supernova involving a ‘stripped’ massive star which has lost its hydrogen – most likely through interactions with a close companion. These interactions typically circularise the pre-SN orbit, and the subsequent explosion most commonly yields neutron stars. To explain the necessarily highly eccentric post-SN orbit that may cause the periodic oscillation in SN2022jli, there was most likely a ‘natal kick’ – a sudden and asymmetric burst during the supernova which rockets the NS in a random direction – which widened the orbit and de-circularised it, giving further evidence for a NS remnant.
Immediately following the SN explosion, ejecta interacting with the main-sequence companion star would heat it and cause it to swell up. This inflated companion then feeds matter to the orbiting dense NS, and the accretion is most intense when the stars are closest in their orbit (called the periastron). During accretion, however, mass is not perfectly absorbed onto the neutron star and there is some feedback process onto the surrounding gas due to the complex thermal and magnetic physics around the NS. In this study, the authors model cases where there is no feedback, feedback from thermal radiation due to accretion, or feedback from bipolar outflows via jets or disk winds. Snapshots from the simulation involving a 5 solar mass companion, on an orbit with eccentricity of 0.5 and bipolar feedback is shown in Figure 2.
Figure 2: Several density snapshots of the 3D hydrodynamic simulations show how the neutron star in the binary (blue point) accretes and sculpts matter from the inflated main-sequence companion star (bright diffuse blob in the centre of each panel). The xy panels are a top-down look onto the orbital plane, while the xz and yz panels show a cross section through the plane. Source: Figure 3 in today’s paper.
The authors evolve the simulation for several orbits and show that periodic bursts of accretion onto the neutron star are capable of producing the oscillatory behaviour seen in SN2022jli’s light curve. The scale of the brightness oscillations are best recreated if the plane of the binary’s orbit is aligned with our line of sight (shown with the +x red line on the right side of Figure 1). Still, the profile of the undulations are not exactly reproduced by the model, and it is very sensitive to our viewing angle of the binary orbit.
SN2022jli is just one of an emerging class of oscillatory supernovae — more and more are being discovered with modern highly-sensitive all-sky surveys. Today’s authors rigorously modelled one proposed scenario to explain this periodic oscillation in brightness and showed that it is viable. More modelling using this interacting-binary mechanism on other oscillating SN light curves – those with longer periods and different SN classifications – will show whether this explanation is ubiquitous, or if the population of dancing SN light curves is due to some other process!
Astrobite edited by Anavi Uppal
Featured image credit: [Neutron star:] NOIRLab/NSF/AURA/J. da Silva/Spaceengine, [Duck:] Kiernan McCloskey/Flickr, [Background:] Hirai et al 2025.
